Bug? Board layout different on first returning to a game after starting the app

Whether starting a new game or resuming an existing one, when I first start the Android app and choose the game, the screen layout is spaced out. There are gaps above and below the board and no space for adverts to be displayed at the bottom of the screen. If the Android app is still running and I go back to the app and choose a game, the screen layout is different, with no spacing. The player header, board, tiles and buttons are joined by a space at the bottom of the screen. What gives?